1. Field of the Invention
The present invention relates to semiconductor devices. In particular, the present invention relates to semiconductor devices each mounted with a memory. Further, the present invention relates to electronic devices mounted with the semiconductor devices
2. Description of the Related Art
Regarding a semiconductor device mounted with a memory, the performance of the memory is extremely important because the performance of the semiconductor device depends on it. For example, as to a semiconductor device mounted with a CPU and a memory, commands to be processed by the CPU and data necessary for the processing need to be stored in the memory. Further, processing by the CPU is progressed by sequential reading of the data in the memory. In other words, as to a semiconductor device mounted with a CPU and a memory, in order to achieve higher performance, the CPU needs to be able to handle more complicated processes, and this requires a high-capacity memory. Furthermore, as for a semiconductor device mounted with a memory, the power consumption of the memory accounts for much of the power consumption of the semiconductor device, in many cases.
In Reference 1 (Hiroki Dembo, et al. “RFCPUs on Glass and Plastic Substrates fabricated by TFT Transfer Technology” IEEE, TECHNICAL DIGEST OF INTERNATIONAL ELECTRON DEVICES MEETING, Dec. 5, 2005, pp. 1067-1069), which one of the present inventors co-wrote, an RFID (Radio Frequency Identification) device (hereinafter referred to as RFID) mounted with a CPU (Central Processing Unit) and a memory is disclosed as an example of a semiconductor device mounted with a memory. For such an RFID, performance of achieving both increase in memory capacity and reduction in power consumption, which is difficult to be achieved, is required in order to achieve higher performance.